Various hardware and software elements in the SNA environment are required in order for two TPs to communicate with each other. The following figure illustrates several fundamental elements:
Each TP is associated with a logical unit (LU) of type 6.2. The LU allows the TP to access the network. Note that several TPs can be associated with the same LU.
A partner TP can invoke another TP, which, in turn, invokes another TP, and so on. In the following figure, TP A invokes TP B, and TP B invokes TP C.
